The present invention relates to a spinning rotor for an open-end spinning unit of the type having an intake portion whose cross section widens in the direction toward the fiber collection trough and which, while forming a projection to effectively widen the rotor diameter, defines one part of the fiber collection trough. The side of the fiber collection trough which is opposite the projection is defined by the spinning rotor bottom surface.
In many cases, it occurs unavoidably that dirt such as, for example, dust, pieces of shell, etc., contained in the fiber material to be processed in the open-end spinning unit forms deposits, particularly in the region of the fiber collection trough.
Such deposits may also be produced by pieces of fiber which are formed as a result of too much stress on the fiber material during the breaking up process.
The deposits produced as a result of dirt and broken fibers will gradually clog the fiber collection trough or the spinning grooves of the spinning rotor so that the quality of the yarn leaving the spinning rotor is reduced and finally breaks occur in the yarn.
To overcome these drawbacks it has already been proposed to design a spinning rotor with a conically tapered intake portion in a manner such that the fiber collecting trough following the intake portion presents certain angles and dimensions with respect to the diameter at the bottom of the trough.
In particular, the diameter of the fiber collecting trough measured from the bottom of the trough should be at least seven times greater than the height or average height of the upper opening edge located above the bottom of the trough.
Based on the goal of providing optimum drawing of the fibers before they are deposited in the fiber collecting area, and thus of producing a yarn with high tensile strength, it has also been proposed to use a spinning rotor with a conically tapered intake portion which forms a projection to increase the rotor diameter and then constitutes the fiber collecting trough. The inner wall portion forming the fiber collecting trough in this case has a diameter which increases in the direction toward the bottom surface of the spinning rotor.